1. Field of the Invention
The present invention relates to a clock lock and more particularly to a clock lock mounted on a door on a safe, an emergency outlet or the like to effect unlocking at a preset time.
2. Description of the Prior Art
As is well known, a time lock having a clock mechanism incorporated therein to effect unlocking only at a required time is hitherto mounted on a door on a safe, an emergency outlet or the like. The conventional clock mechanism is constituted by a movement including a spiral spring as main component and its unlocking operation is initiated by mechanical actuating means such as lever or the like which is operatively connected to locking section so as to unlock the locking section with resilient force of the spiral spring which is amplified or enlarged by means of the lever. Due to arrangement of the conventional clock mechanism made in that way it results that unlocking time is roughly set, there is a necessity for making certain allowances for the period of unlocking time, its actuation lacks stability and moreover there is a fear of causing long delay from the preset unlocking time. In principle, the conventional clock mechanism is intended to set relative time and therefore there is a possibility of causing such a malfunction that unlocking is effected at unexpected incorrect time when time calculation with respect to the number of hours as counted from the existing time fails to be made properly. Further, the conventional clock mechanism is generally constituted such that a plurality of movements have to be set to assume their position in alignment with individual calibration line but any malfunction tends to be detected with much delay, because locking can be effected again even when any one of the movements fails to function properly.